1. Field of the Invention
The field of invention pertains to wrenches, and more particularly pertains to that class of oil filter wrenches particularly adapted for the removal and installation of automotive type canister oil filters.
2. Description of the Prior Art
Oil filter wrenches are of a class of tool that is indispensable in contemporary automotive environments. An automotive type oil filter canister, even when secured to an automotive engine in a hand-tight torquing procedure, the normal heating and contraction of the oil filter cannister in use of the automobile tends to tighten the oil filter to the automobile engine making manual removal very difficult, if not impossible. Consequently, oil filter wrenches are utilized and come in a variety of types such as a band type using an encircling band about the oil filter, or an over-the-end socket type and the like.
Modern automobiles in the evolution of development are currently utilizing oil filters of varying diameters. As a consequence, a mechanic must have on hand a variety of such oil filter wrenches and keep them in order. This is not always possible due to the nature of business and is a further complication to a business environment as well as an individual who performs an oil filter change as a manner of routine maintenance. Examples of encircling type wrenches are set forth for example in U.S. Pat. No. 1,388,083 to Workman wherein a pivoted band provided with serrated interior is formed with associated handles for gripping about a lid of a container. The Workman patent, as is typical of the prior art, provides no basis for adjustment.
U.S Pat. No. 3,964,115 to Platek sets forth a band type wrench of a relatively complex and elaborate construction utilizing a flaccid belt that is adjustable dependent on the diameter of objects to be rotated. Unfortunately, the Platek patent and the use of a flaccid loop is not of a convenient organization due to the need to manipulate and maneuver a loop that does not maintain its configurational integrity when positioned and oriented within a confined engine compartment and furthermore is of a rather extensive structural organization that limits its accessability within contemporary tight engine compartments.
U.S. Pat. No. 4,350,063 to Koehler sets forth a spring band of material adjustable for diameter by use of a worm screw engageable with slots on the band wherein the worm screw forms an extension that is a shank of a twist tool. The Koehler patent is of limited strength and will tend to deform and bind the manipulation of canister type oil filters as the worm screw and shank are offset and tangential to the band and fail to provide a circumferential pressure over an extended surface of the band material, as does the instant invention.
U.S. Pat. No. 4,506,568 to Aamodt sets forth a strap wrench that is adjustable by means of a two-part twisting interengageable socket arrangement to adjust the loop diameter of a strap wrench, as may be typically utilized for removal of oil filters, but is of similar structural limitations as other the prior art as in the Platek patent and the use of flaccid loops in the manipulation of automotive oil filters.
U.S. Pat. No. 4,552,040 to Bang sets forth a loop wherein the ends thereof are relatively positionable relative to one another by means of a threaded shank and is of a similar organization to that as the Koehler patent wherein the torque application handle is tangentially offset relative to the surface of an associated oil filter and thereby tends to bind and limit the strength of such wrenches.
As may be appreciated, there continues to exist a need for a new and improved adjustable oil wrench that provides the features of adjustability, strength, and application of circumferentially applied force directly to the surface of an oil filter, and in this respect, the present invention substantially fulfills this need.